Looking for some guidance on where to buy spur gears. They are for a little project in the garden - idea is to attach them onto the end of threaded rod to make a kind of linear actuator. I have no particular requirement for precision - but they probably need to be made out of medal to take the load.

The problem I'm having is three-fold:

- lots of the cheaper gears I've found are made of nylon or model size (like 1-2mm shaft diameter)- I've found larger gears, but they are pretty expensive (£30 a gear)- also - the larger gears are generally locked onto the shaft with a keyway, but I dont have access to a milling machine, so a set/grub screw is far preferable.

ideal would be a source of cheap metal spur gears with set screws with shaft diameter roughly an M6.